The field of the invention is systems and methods for focused ultrasound. More particularly, the invention relates to a focused ultrasound system capable of use in small bore imaging systems.
The present invention relates generally to a system and method of focused ultrasound application and, more particularly, to a focused ultrasound system that provides precise spatial positioning under the guidance of a medical imaging system to deliver focused ultrasound to a target location. More specifically, the present invention is a focused ultrasound (“FUS”) system in which the target volume(s) for sonication are determined using an imaging apparatus.
Focused ultrasound therapy involves delivering ultrasound energy to localized regions of tissue from externally (non-invasive) or internally (minimally-invasive) located transducers. The amount of ultrasound energy delivered to tissue dictates the nature of the biologic effect produced at that location. At high intensities with continuous exposure, ultrasound energy can generate enough heat to cause irreversible thermal damage through coagulation. As the exposure is reduced in duty cycle to short pulses, the mechanical energy associated with ultrasound dominates and can be used to generate a range of bio-effects, including: vascular occlusion or hemorrhage, permeation of cells, and tissue-homogenization. The combination of FUS with microbubbles can generate additional bio-effects, including sonoporation and increasing of the permeability of the blood brain barrier.
Often, imaging with small animal models is performed in customized systems designed for these species. In order to maximize signal to noise ratio and sensitivity, these systems are generally designed specifically for rodents, and as a result have small openings or bores. As an example, high-field MRI systems have bore diameters of 5-20 cm, which is sufficient for a mouse or rat, but makes insertion of a focused ultrasound system challenging.
It would therefore be desirable to have a focused ultrasound system that was capable of exposing targets defined using dedicated small animal imaging systems having small bores, such as bores that are smaller than 154 millimeters.